Merge remote-tracking branch 'origin/master' into composite

configs/clicker2-stm32/README.txt

@@ -603,7 +603,7 @@ Configurations
          CONFIG_NET_STAR=y
          CONFIG_NET_STARPOINT=y
 
-       The CONFIG_NET_STARPOINT selection informs the endpoint that is
+       The CONFIG_NET_STARPOINT selection informs the endpoint that it
        must send all frames to the hub of the star, rather than directly
        to the recipient.
 
@@ -649,17 +649,43 @@ Configurations
 
        Where <server-ip> is the IP address of the E1 endpoint.
 
+       Similarly for the UDP test:
+
+         E1: nsh> udpserver &
+         E2: nsh> udpclient <server-ip> &
+
        The nsh> dmesg command can be use at any time on any node to see
        any debug output that you have selected.
 
-       Telenet sessions may be initiated from the hub:
+       Telenet sessions may be initiated only from the hub to a star
+       endpoint:
 
          C: nsh> telnet <server-ip> <-- Runs the Telnet client
 
        Where <server-ip> is the IP address of either the E1 or I2 endpoints.
 
     STATUS:
-      2017-06-29:  Configurations added but not yet tested.
+      2017-06-29:  Configurations added.  Initial testing indicates that
+        the TCP Telnet client can successfully establish sessions with
+        the two star endpoints.  When testing communications between the
+        two star endpoints via the hub, the frames are correctly directed
+        to the hub.  However, they are not being forwarded to the other
+        endpoint.
+      2017-06-30: The failure to forward is understood:  When the star
+        endpoint sent the IPv6 destination address, the HC06 compression
+        logic elided the address -- meaning that it could be reconstructed
+        based on the receiver's assigned short address.  However, when
+        intercepted by the hub, the uncompressed address does not know
+        the short address of the recipient and instead uses the short
+        address of the hub.  This means two things:  (1) it looks like
+        the hub address is the destination address, and (2) the
+        uncompressed UDP packet has a bad checksum.
+
+        This required a change to assure that the destination IPv6 address
+        is not elided in the case of the star endpoint configuration.  After
+        some additional fixes for byte ordering in 16-bit and 64-bit
+        compressed IPv6 addresses, the all tests are working as expectedd:
+        TCP, UDP, Telnet.
 
   nsh:
 

configs/clicker2-stm32/mrf24j40-6lowpan/defconfig

@@ -992,9 +992,7 @@ CONFIG_NET_6LOWPAN_MAXAGE=20
 CONFIG_NET_6LOWPAN_MAX_MACTRANSMITS=4
 CONFIG_NET_6LOWPAN_MTU=1294
 CONFIG_NET_6LOWPAN_TCP_RECVWNDO=1220
-CONFIG_NET_HAVE_STAR=y
 # CONFIG_NET_IPFORWARD is not set
-# CONFIG_NET_STAR is not set
 
 #
 # Socket Support
@@ -1060,6 +1058,12 @@ CONFIG_NET_UDP_READAHEAD=y
 # CONFIG_NET_ARCH_INCR32 is not set
 # CONFIG_NET_ARCH_CHKSUM is not set
 CONFIG_NET_STATISTICS=y
+CONFIG_NET_HAVE_STAR=y
+
+#
+# Network Topologies
+#
+# CONFIG_NET_STAR is not set
 
 #
 # Routing Table Configuration

configs/sim/sixlowpan/defconfig

@@ -556,9 +556,7 @@ CONFIG_NET_6LOWPAN_MAXAGE=20
 CONFIG_NET_6LOWPAN_MAX_MACTRANSMITS=4
 CONFIG_NET_6LOWPAN_MTU=1294
 CONFIG_NET_6LOWPAN_TCP_RECVWNDO=102
-CONFIG_NET_HAVE_STAR=y
 # CONFIG_NET_IPFORWARD is not set
-# CONFIG_NET_STAR is not set
 
 #
 # Socket Support
@@ -625,6 +623,12 @@ CONFIG_NET_UDP_READAHEAD=y
 # CONFIG_NET_ARCH_INCR32 is not set
 # CONFIG_NET_ARCH_CHKSUM is not set
 CONFIG_NET_STATISTICS=y
+CONFIG_NET_HAVE_STAR=y
+
+#
+# Network Topologies
+#
+# CONFIG_NET_STAR is not set
 
 #
 # Routing Table Configuration

net/sixlowpan/README.txt

@@ -1,3 +1,11 @@
+6LoWPAN Contents
+----------------
+
+  o 6LoWPAN Addressing
+  o IPv6 Neighbor Discovery
+  o Optimal 6LoWPAN Configuration
+  o Star Configuration
+
 6LoWPAN Addressing
 ------------------
 
@@ -142,3 +150,28 @@ The payload length is encoded in the LS 11-bits of the first 16-bit value:
 In this example the payload size is 0x050e or 1,294.  The tag is 0x000b.  In
 the second frame, the fifth byte contains the offset 0x0d which is 13 << 3 =
 104 bytes, the size of the payload on the first packet.
+
+Star Configuration
+------------------
+
+The 6LoWPAN stack can be specially configured as member in a star topology;
+either as a endpoint on the star os the star hub.  The endpoint is
+created with the following settings in the configuration file:
+
+  CONFIG_NET_STAR=y
+  CONFIG_NET_STARPOINT=y
+
+The CONFIG_NET_STARPOINT selection informs the endpoint 6LoWPAN stack that
+it must send all frames to the hub of the star, rather than directly to the
+recipient.  The star hub is assumed to be the cooordinator.
+
+The star hub configuration, on the other hand, uses these setting:
+
+  CONFIG_NET_STAR=y
+  CONFIG_NET_STARHUB=y
+  CONFIG_NET_IPFORWARD=y
+
+The CONFIG_NET_IPFORWARD selection informs the hub that if it receives any
+packets that are not destined for the hub, it should forward those packets
+appropriately.  This affects the behavior of IPv6 packet reception logic but
+does not change the behavior of the 6LoWPAN stack.

net/sixlowpan/sixlowpan_framelist.c

@@ -324,22 +324,7 @@ int sixlowpan_queue_frames(FAR struct ieee802154_driver_s *ieee,
                       &ieee->i_dev.d_mac.ieee802154);
 #endif
 
-#ifdef CONFIG_NET_STARPOINT
+  /* Copy the destination node address into the meta data */
-  /* If this node is a "point" in a star topology, then the destination
-   * MAC address is the address of the hub/PAN coordinator.
-   */
-
-  if (destmac->extended)
-    {
-      pktmeta.dextended = TRUE;
-      ret = sixlowpan_coord_eaddr(ieee, pktmeta.dest.eaddr.u8);
-    }
-  else
-    {
-      ret = sixlowpan_coord_saddr(ieee, pktmeta.dest.saddr.u8);
-    }
-#else
-  /* Otherwise, it is the actual destination node address */
 
   if (destmac->extended)
     {
@@ -350,7 +335,6 @@ int sixlowpan_queue_frames(FAR struct ieee802154_driver_s *ieee,
     {
       sixlowpan_saddrcopy(pktmeta.dest.saddr.u8, destmac->u.saddr.u8);
     }
-#endif
 
   /* Get the destination PAN ID.
    *

net/sixlowpan/sixlowpan_hc06.c

@@ -251,16 +251,23 @@ static uint8_t compress_ipaddr(FAR const net_ipv6addr_t ipaddr, uint8_t bitpos)
     {
       /* Compress IID to 16 bits: xxxx:xxxx:xxxx:xxxx:0000:00ff:fe00:XXXX */
 
-      memcpy(g_hc06ptr, &ipaddr[7], 2);
+      *g_hc06ptr++ = ipaddr[7] >> 8;      /* Big-endian, network order */
-      g_hc06ptr += 2;
+      *g_hc06ptr++ = ipaddr[7] & 0xff;
+
       return 2 << bitpos;       /* 16-bits */
     }
   else
     {
+      int i;
+
       /* Do not compress IID: xxxx:xxxx:xxxx:xxxx:IID:IID:IID:IID */
 
-      memcpy(g_hc06ptr, &ipaddr[4], 8);
+      for (i = 4; i < 8; i++)
-      g_hc06ptr += 8;
+        {
+          *g_hc06ptr++ = ipaddr[i] >> 8;  /* Big-endian, network order */
+          *g_hc06ptr++ = ipaddr[i] & 0xff;
+        }
+
       return 1 << bitpos;       /* 64-bits */
     }
 }
@@ -429,6 +436,8 @@ static void uncompress_addr(FAR const struct ieee802154_addr_s *addr,
 
           for (i = destndx; i < 8; i++)
             {
+              /* Big-endian, network order */
+
               ipaddr[i] = (uint16_t)srcptr[0] << 8 | (uint16_t)srcptr[1];
               srcptr += 2;
             }
@@ -437,11 +446,11 @@ static void uncompress_addr(FAR const struct ieee802154_addr_s *addr,
 
           if (fullmac)
             {
-              ipaddr[destndx] ^= 0x200;
+              ipaddr[destndx] ^= 0x0200;
             }
         }
 
-      /* postcount is odd... */
+      /* postcount is odd... REVISIT:  I am not sure about bye ordering. */
 
       else
         {
@@ -849,13 +858,13 @@ int sixlowpan_compresshdr_hc06(FAR struct ieee802154_driver_s *ieee,
         {
           /* Elide the prefix */
 
-          iphc1 |= SIXLOWPAN_IPHC_DAC;
+          iphc1   |= SIXLOWPAN_IPHC_DAC;
           iphc[2] |= addrcontext->number;
 
           /* Compession compare with link adress (destination) */
 
-          iphc1 |= compress_tagaddr(ipv6->destipaddr, destmac,
+          iphc1   |= compress_tagaddr(ipv6->destipaddr, destmac,
-                                    SIXLOWPAN_IPHC_DAM_BIT);
+                                      SIXLOWPAN_IPHC_DAM_BIT);
         }
 
       /* No address context found for this address */

net/sixlowpan/sixlowpan_input.c

@@ -830,7 +830,13 @@ int sixlowpan_input(FAR struct ieee802154_driver_s *ieee,
                    * address.
                    */
 
-                  sixlowpan_addrfromip(ipv6hdr->destipaddr, &destmac);
+                  ret = sixlowpan_destaddrfromip(ieee, ipv6hdr->destipaddr,
+                                                 &destmac);
+                  if (ret < 0)
+                    {
+                      nerr("ERROR: Failed to dest MAC address: %d\n", ret);
+                      goto drop;
+                    }
 
                   /* The data payload should follow the IPv6 header plus
                    * the protocol header.

net/sixlowpan/sixlowpan_internal.h

@@ -536,25 +536,28 @@ int sixlowpan_uncompresshdr_hc1(FAR const struct ieee802154_data_ind_s *ind,
 #endif
 
 /****************************************************************************
- * Name: sixlowpan_islinklocal, sixlowpan_addrfromip, and
+ * Name: sixlowpan_islinklocal, sixlowpan_destaddrfromip, and
  *       sixlowpan_ismacbased
  *
  * Description:
- *   sixlowpan_{s|e]addrfromip(): Extract the IEEE 802.15.14 address from a
+ *   sixlowpan_destaddrfromip(): Extract the IEEE 802.15.14 destination
- *   MAC-based IPv6 address.  sixlowpan_addrfromip() is intended to handle a
+ *   address from a MAC-based destination IPv6 address.  This function
- *   tagged address; sixlowpan_saddrfromip() and sixlowpan_eaddrfromip()
+ *   handles a tagged address union which may either a short or and
- *   specifically handle short and extended addresses, respectively.
+ *   extended destination address.
+ *
+ *   In the case there the IEEE 802.15.4 node functions as an endpoint in a
+ *   start topology, the destination address will, instead, be the address
+ *   of the star hub (which is assumed to be the address of the cooordinator).
  *
  *   sixlowpan_ipfrom[s|e]addr():  Create a link-local, MAC-based IPv6
  *   address from an IEEE802.15.4 short address (saddr) or extended address
  *   (eaddr).
  *
  *   sixlowpan_islinklocal() and sixlowpan_ismacbased() will return true for
- *   address created in this fashion.  sixlowpan_addrfromip() is intended to
+ *   address created in this fashion.  sixlowpan_destaddrfromip() is intended to
- *   handle a tagged address or any size; sixlowpan_issaddrbased() and
+ *   handle a tagged address or any size.  Local addresses are of a fixed but
- *   sixlowpan_iseaddrbased() specifically handle short and extended
+ *   configurable size and sixlowpan_isaddrbased() is for use with such local
- *   addresses.  Local addresses are of a fixed but configurable size and
+ *   addresses.
- *   sixlowpan_isaddrbased() is for use with such local addresses.
  *
  *    128  112  96   80    64   48   32   16
  *    ---- ---- ---- ----  ---- ---- ---- ----
@@ -565,12 +568,9 @@ int sixlowpan_uncompresshdr_hc1(FAR const struct ieee802154_data_ind_s *ind,
 
 #define sixlowpan_islinklocal(ipaddr) ((ipaddr)[0] == NTOHS(0xfe80))
 
-void sixlowpan_saddrfromip(const net_ipv6addr_t ipaddr,
+int sixlowpan_destaddrfromip(FAR struct ieee802154_driver_s *ieee,
-                           FAR struct sixlowpan_saddr_s *saddr);
+                             const net_ipv6addr_t ipaddr,
-void sixlowpan_eaddrfromip(const net_ipv6addr_t ipaddr,
+                             FAR struct sixlowpan_tagaddr_s *addr);
-                           FAR struct sixlowpan_eaddr_s *eaddr);
-void sixlowpan_addrfromip(const net_ipv6addr_t ipaddr,
-                          FAR struct sixlowpan_tagaddr_s *addr);
 
 void sixlowpan_ipfromsaddr(FAR const uint8_t *saddr,
                            FAR net_ipv6addr_t ipaddr);
@@ -593,46 +593,6 @@ bool sixlowpan_iseaddrbased(const net_ipv6addr_t ipaddr,
 bool sixlowpan_ismacbased(const net_ipv6addr_t ipaddr,
                           FAR const struct sixlowpan_tagaddr_s *addr);
 
-/****************************************************************************
- * Name: sixlowpan_coord_eaddr
- *
- * Description:
- *   Get the extended address of the PAN coordinator.
- *
- * Input parameters:
- *   ieee  - A reference IEEE802.15.4 MAC network device structure.
- *   eaddr - The location in which to return the extended address.
- *
- * Returned Value:
- *   Zero (OK) on success; a negated errno value on failure.
- *
- ****************************************************************************/
-
-#ifdef CONFIG_NET_STARPOINT
-int sixlowpan_coord_eaddr(FAR struct ieee802154_driver_s *ieee,
-                          FAR uint8_t *eaddr);
-#endif
-
-/****************************************************************************
- * Name: sixlowpan_coord_saddr
- *
- * Description:
- *   Get the short address of the PAN coordinator.
- *
- * Input parameters:
- *   ieee  - A reference IEEE802.15.4 MAC network device structure.
- *   saddr - The location in which to return the short address.
- *
- * Returned Value:
- *   Zero (OK) on success; a negated errno value on failure.
- *
- ****************************************************************************/
-
-#ifdef CONFIG_NET_STARPOINT
-int sixlowpan_coord_saddr(FAR struct ieee802154_driver_s *ieee,
-                          FAR uint8_t *saddr);
-#endif
-
 /****************************************************************************
  * Name: sixlowpan_src_panid
  *

net/sixlowpan/sixlowpan_tcpsend.c

@@ -417,6 +417,7 @@ static uint16_t tcp_send_interrupt(FAR struct net_driver_s *dev,
            * actually sent.
            */
 
+          sinfo->s_result = sinfo->s_sent;
           goto end_wait;
         }
 
@@ -835,7 +836,13 @@ ssize_t psock_6lowpan_tcp_send(FAR struct socket *psock, FAR const void *buf,
    * an encoding of the MAC address in the IPv6 address.
    */
 
-  sixlowpan_addrfromip(conn->u.ipv6.raddr, &destmac);
+  ret = sixlowpan_destaddrfromip((FAR struct ieee802154_driver_s *)dev,
+                                 conn->u.ipv6.raddr, &destmac);
+  if (ret < 0)
+    {
+      nerr("ERROR: Failed to dest MAC address: %d\n", ret);
+      return (ssize_t)ret;
+    }
 
   /* Set the socket state to sending */
 
@@ -859,7 +866,7 @@ ssize_t psock_6lowpan_tcp_send(FAR struct socket *psock, FAR const void *buf,
       nerr("ERROR: sixlowpan_send_packet() failed: %d\n", ret);
 
       psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_IDLE);
-      return (ssize_t)buflen;
+      return (ssize_t)ret;
     }
 
   /* Set the socket state to idle */
@@ -942,12 +949,19 @@ void sixlowpan_tcp_send(FAR struct net_driver_s *dev,
           FAR uint8_t *buf;
           uint16_t hdrlen;
           uint16_t buflen;
+          int ret;
 
           /* Get the IEEE 802.15.4 MAC address of the destination.  This
            * assumes an encoding of the MAC address in the IPv6 address.
            */
 
-          sixlowpan_addrfromip(ipv6hdr->ipv6.destipaddr, &destmac);
+          ret = sixlowpan_destaddrfromip((FAR struct ieee802154_driver_s *)dev,
+                                         ipv6hdr->ipv6.destipaddr, &destmac);
+          if (ret < 0)
+            {
+              nerr("ERROR: Failed to dest MAC address: %d\n", ret);
+              goto drop;
+            }
 
           /* Get the IPv6 + TCP combined header length.  The size of the TCP
            * header is encoded in the top 4 bits of the tcpoffset field (in
@@ -977,6 +991,7 @@ void sixlowpan_tcp_send(FAR struct net_driver_s *dev,
         }
     }
 
+drop:
   dev->d_len = 0;
 }
 

net/sixlowpan/sixlowpan_udpsend.c

@@ -297,15 +297,21 @@ ssize_t psock_6lowpan_udp_sendto(FAR struct socket *psock,
   g_netstats.udp.sent++;
 #endif
 
-  /* Set the socket state to sending */
-
-  psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_SEND);
-
   /* Get the IEEE 802.15.4 MAC address of the destination  This assumes an
    * encoding of the MAC address in the IPv6 address.
    */
 
-  sixlowpan_addrfromip(to6->sin6_addr.in6_u.u6_addr16, &destmac);
+  ret = sixlowpan_destaddrfromip((FAR struct ieee802154_driver_s *)dev,
+                                 to6->sin6_addr.in6_u.u6_addr16, &destmac);
+  if (ret < 0)
+    {
+      nerr("ERROR: Failed to dest MAC address: %d\n", ret);
+      return (ssize_t)ret;
+    }
+
+  /* Set the socket state to sending */
+
+  psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_SEND);
 
   /* If routable, then call sixlowpan_send() to format and send the 6LoWPAN
    * packet.
@@ -328,7 +334,7 @@ ssize_t psock_6lowpan_udp_sendto(FAR struct socket *psock,
   /* Set the socket state to idle */
 
   psock->s_flags = _SS_SETSTATE(psock->s_flags, _SF_IDLE);
-  return ret;
+  return (ssize_t)ret;
 }
 
 /****************************************************************************
@@ -465,12 +471,19 @@ void sixlowpan_udp_send(FAR struct net_driver_s *dev,
           FAR uint8_t *buf;
           uint16_t hdrlen;
           uint16_t buflen;
+          int ret;
 
           /* Get the IEEE 802.15.4 MAC address of the destination.  This
            * assumes an encoding of the MAC address in the IPv6 address.
            */
 
-          sixlowpan_addrfromip(ipv6udp->ipv6.destipaddr, &destmac);
+          ret = sixlowpan_destaddrfromip((FAR struct ieee802154_driver_s *)dev,
+                                         ipv6udp->ipv6.destipaddr, &destmac);
+          if (ret < 0)
+            {
+              nerr("ERROR: Failed to dest MAC address: %d\n", ret);
+              goto drop;
+            }
 
           /* Get the IPv6 + UDP combined header length. */
 
@@ -497,6 +510,7 @@ void sixlowpan_udp_send(FAR struct net_driver_s *dev,
         }
     }
 
+drop:
   dev->d_len = 0;
 }
 #endif

net/sixlowpan/sixlowpan_utils.c

@@ -64,17 +64,17 @@
 #ifdef CONFIG_NET_6LOWPAN
 
 /****************************************************************************
- * Public Functions
+ * Private Functions
  ****************************************************************************/
 
 /****************************************************************************
- * Name: sixlowpan_{s|e]addrfromip
+ * Name: sixlowpan_[s|e]addrfromip
  *
  * Description:
- *   sixlowpan_{s|e]addrfromip(): Extract the IEEE 802.15.14 address from a
+ *   sixlowpan_[s|e]addrfromip(): Extract the IEEE 802.15.14 address from a
- *   MAC-based IPv6 address.  sixlowpan_addrfromip() is intended to handle a
+ *   MAC-based IPv6 address.  sixlowpan_saddrfromip() and
- *   tagged address; sixlowpan_saddrfromip() and sixlowpan_eaddrfromip()
+ *   sixlowpan_eaddrfromip() handle short and extended addresses,
- *   specifically handle short and extended addresses, respectively.
+ *   respectively.
  *
  *    128  112  96   80    64   48   32   16
  *    ---- ---- ---- ----  ---- ---- ---- ----
@@ -83,8 +83,9 @@
  *
  ****************************************************************************/
 
-void sixlowpan_saddrfromip(const net_ipv6addr_t ipaddr,
+#ifndef CONFIG_NET_STARPOINT
-                          FAR struct sixlowpan_saddr_s *saddr)
+static void sixlowpan_saddrfromip(const net_ipv6addr_t ipaddr,
+                                  FAR struct sixlowpan_saddr_s *saddr)
 {
   DEBUGASSERT(ipaddr[0] == HTONS(0xfe80));
 
@@ -95,8 +96,8 @@ void sixlowpan_saddrfromip(const net_ipv6addr_t ipaddr,
   saddr->u8[0] ^= 0x02;
 }
 
-void sixlowpan_eaddrfromip(const net_ipv6addr_t ipaddr,
+static void sixlowpan_eaddrfromip(const net_ipv6addr_t ipaddr,
-                          FAR struct sixlowpan_eaddr_s *eaddr)
+                                  FAR struct sixlowpan_eaddr_s *eaddr)
 {
   FAR uint8_t *eptr = eaddr->u8;
   int i;
@@ -113,22 +114,147 @@ void sixlowpan_eaddrfromip(const net_ipv6addr_t ipaddr,
 
   eaddr->u8[0] ^= 0x02;
 }
+#endif /* !CONFIG_NET_STARPOINT */
 
-void sixlowpan_addrfromip(const net_ipv6addr_t ipaddr,
+/****************************************************************************
-                          FAR struct sixlowpan_tagaddr_s *addr)
+ * Name: sixlowpan_coord_eaddr
+ *
+ * Description:
+ *   Get the extended address of the PAN coordinator.
+ *
+ * Input parameters:
+ *   ieee  - A reference IEEE802.15.4 MAC network device structure.
+ *   eaddr - The location in which to return the extended address.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+#if defined(CONFIG_NET_STARPOINT) && defined(CONFIG_NET_6LOWPAN_EXTENDEDADDR)
+static int sixlowpan_coord_eaddr(FAR struct ieee802154_driver_s *ieee,
+                                 FAR struct sixlowpan_eaddr_s *eaddr)
 {
+  FAR struct net_driver_s *dev = &ieee->i_dev;
+  struct ieee802154_netmac_s arg;
+  int ret;
+
+  memcpy(arg.ifr_name, ieee->i_dev.d_ifname, IFNAMSIZ);
+  arg.u.getreq.attr = IEEE802154_ATTR_MAC_COORD_EADDR ;
+  ret = dev->d_ioctl(dev, MAC802154IOC_MLME_GET_REQUEST,
+                     (unsigned long)((uintptr_t)&arg));
+  if (ret < 0)
+    {
+      nerr("ERROR: MAC802154IOC_MLME_GET_REQUEST failed: %d\n", ret);
+      return ret;
+    }
+
+  IEEE802154_EADDRCOPY(eaddr->u8, arg.u.getreq.attrval.mac.eaddr);
+  return OK;
+}
+#endif
+
+/****************************************************************************
+ * Name: sixlowpan_coord_saddr
+ *
+ * Description:
+ *   Get the short address of the PAN coordinator.
+ *
+ * Input parameters:
+ *   ieee  - A reference IEEE802.15.4 MAC network device structure.
+ *   saddr - The location in which to return the short address.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno value on failure.
+ *
+ ****************************************************************************/
+
+#if defined(CONFIG_NET_STARPOINT) && !defined(CONFIG_NET_6LOWPAN_EXTENDEDADDR)
+static int sixlowpan_coord_saddr(FAR struct ieee802154_driver_s *ieee,
+                                 FAR struct sixlowpan_saddr_s *saddr)
+{
+  FAR struct net_driver_s *dev = &ieee->i_dev;
+  struct ieee802154_netmac_s arg;
+  int ret;
+
+  memcpy(arg.ifr_name, ieee->i_dev.d_ifname, IFNAMSIZ);
+  arg.u.getreq.attr = IEEE802154_ATTR_MAC_COORD_SADDR ;
+  ret = dev->d_ioctl(dev, MAC802154IOC_MLME_GET_REQUEST,
+                     (unsigned long)((uintptr_t)&arg));
+  if (ret < 0)
+    {
+      nerr("ERROR: MAC802154IOC_MLME_GET_REQUEST failed: %d\n", ret);
+      return ret;
+    }
+
+  IEEE802154_SADDRCOPY(saddr->u8, arg.u.getreq.attrval.mac.saddr);
+  return OK;
+}
+#endif
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: sixlowpan_destaddrfromip
+ *
+ * Description:
+ *   sixlowpan_destaddrfromip(): Extract the IEEE 802.15.14 destination
+ *   address from a MAC-based destination IPv6 address.  This function
+ *   handles a tagged address union which may either a short or and
+ *   extended destination address.
+ *
+ *    128  112  96   80    64   48   32   16
+ *    ---- ---- ---- ----  ---- ---- ---- ----
+ *    xxxx 0000 0000 0000  0000 00ff fe00 xxxx 2-byte short address IEEE 48-bit MAC
+ *    xxxx 0000 0000 0000  xxxx xxxx xxxx xxxx 8-byte extended address IEEE EUI-64
+ *
+ *   In the case there the IEEE 802.15.4 node functions as an endpoint in a
+ *   start topology, the destination address will, instead, be the address
+ *   of the star hub (which is assumed to be the address of the cooordinator).
+ *
+ ****************************************************************************/
+
+int sixlowpan_destaddrfromip(FAR struct ieee802154_driver_s *ieee,
+                             const net_ipv6addr_t ipaddr,
+                             FAR struct sixlowpan_tagaddr_s *destaddr)
+{
+#ifdef CONFIG_NET_STARPOINT
+  int ret;
+
+  /* If this node is a "point" in a star topology, then the destination
+   * MAC address is the address of the hub/PAN coordinator.
+   */
+
+#ifdef CONFIG_NET_6LOWPAN_EXTENDEDADDR
+  ret = sixlowpan_coord_eaddr(ieee, &destaddr->u.eaddr);
+  destaddr->extended = true;
+#else
+  memset(destaddr, 0, sizeof(struct sixlowpan_tagaddr_s));
+  ret = sixlowpan_coord_saddr(ieee, &destaddr->u.saddr);
+#endif
+
+  return ret;
+
+#else
   DEBUGASSERT(ipaddr[0] == HTONS(0xfe80));
 
+  /* Otherwise, the destination MAC address is encoded in the IP address */
+
   if (SIXLOWPAN_IS_IID_16BIT_COMPRESSABLE(ipaddr))
     {
-      memset(addr, 0, sizeof(struct sixlowpan_tagaddr_s));
+      memset(destaddr, 0, sizeof(struct sixlowpan_tagaddr_s));
-      sixlowpan_saddrfromip(ipaddr, &addr->u.saddr);
+      sixlowpan_saddrfromip(ipaddr, &destaddr->u.saddr);
     }
   else
     {
-      sixlowpan_eaddrfromip(ipaddr, &addr->u.eaddr);
+      sixlowpan_eaddrfromip(ipaddr, &destaddr->u.eaddr);
-      addr->extended = true;
+      destaddr->extended = true;
     }
+
+  return OK;
+#endif
 }
 
 /****************************************************************************
@@ -179,11 +305,10 @@ void sixlowpan_ipfromeaddr(FAR const uint8_t *eaddr,
  *
  * Description:
  *   sixlowpan_ismacbased() will return true for IP addresses formed from
- *   IEEE802.15.4 MAC addresses.  sixlowpan_addrfromip() is intended to
+ *   IEEE802.15.4 MAC addresses.  sixlowpan_destaddrfromip() is intended to
- *   handle a tagged address or any size; sixlowpan_issaddrbased() and
+ *   handle a tagged address or any size.  Local addresses are of a fixed
- *   sixlowpan_iseaddrbased() specifically handle short and extended
+ *   but configurable size and sixlowpan_isaddrbased() is for use with such
- *   addresses.  Local addresses are of a fixed but configurable size and
+ *   local addresses.
- *   sixlowpan_isaddrbased() is for use with such local addresses.
  *
  *
  *    128  112  96   80    64   48   32   16
@@ -227,82 +352,6 @@ bool sixlowpan_ismacbased(const net_ipv6addr_t ipaddr,
     }
 }
 
-/****************************************************************************
- * Name: sixlowpan_coord_eaddr
- *
- * Description:
- *   Get the extended address of the PAN coordinator.
- *
- * Input parameters:
- *   ieee  - A reference IEEE802.15.4 MAC network device structure.
- *   eaddr - The location in which to return the extended address.
- *
- * Returned Value:
- *   Zero (OK) on success; a negated errno value on failure.
- *
- ****************************************************************************/
-
-#ifdef CONFIG_NET_STARPOINT
-int sixlowpan_coord_eaddr(FAR struct ieee802154_driver_s *ieee,
-                          FAR uint8_t *eaddr)
-{
-  FAR struct net_driver_s *dev = &ieee->i_dev;
-  struct ieee802154_netmac_s arg;
-  int ret;
-
-  memcpy(arg.ifr_name, ieee->i_dev.d_ifname, IFNAMSIZ);
-  arg.u.getreq.attr = IEEE802154_ATTR_MAC_COORD_EADDR ;
-  ret = dev->d_ioctl(dev, MAC802154IOC_MLME_GET_REQUEST,
-                     (unsigned long)((uintptr_t)&arg));
-  if (ret < 0)
-    {
-      nerr("ERROR: MAC802154IOC_MLME_GET_REQUEST failed: %d\n", ret);
-      return ret;
-    }
-
-  IEEE802154_EADDRCOPY(eaddr, arg.u.getreq.attrval.mac.eaddr);
-  return OK;
-}
-#endif
-
-/****************************************************************************
- * Name: sixlowpan_coord_saddr
- *
- * Description:
- *   Get the short address of the PAN coordinator.
- *
- * Input parameters:
- *   ieee  - A reference IEEE802.15.4 MAC network device structure.
- *   saddr - The location in which to return the short address.
- *
- * Returned Value:
- *   Zero (OK) on success; a negated errno value on failure.
- *
- ****************************************************************************/
-
-#ifdef CONFIG_NET_STARPOINT
-int sixlowpan_coord_saddr(FAR struct ieee802154_driver_s *ieee,
-                          FAR uint8_t *saddr)
-{
-  FAR struct net_driver_s *dev = &ieee->i_dev;
-  struct ieee802154_netmac_s arg;
-  int ret;
-
-  memcpy(arg.ifr_name, ieee->i_dev.d_ifname, IFNAMSIZ);
-  arg.u.getreq.attr = IEEE802154_ATTR_MAC_COORD_SADDR ;
-  ret = dev->d_ioctl(dev, MAC802154IOC_MLME_GET_REQUEST,
-                     (unsigned long)((uintptr_t)&arg));
-  if (ret < 0)
-    {
-      nerr("ERROR: MAC802154IOC_MLME_GET_REQUEST failed: %d\n", ret);
-      return ret;
-    }
-
-  IEEE802154_SADDRCOPY(saddr, arg.u.getreq.attrval.mac.saddr);
-  return OK;
-}
-#endif
-
 /****************************************************************************
  * Name: sixlowpan_src_panid
  *